Can You Use Topsoil for Seed Starting? Here are the facts!

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One question that is commonly asked in the gardening world is

“Can you use topsoil to start seeds?”.  

The simple answer to this question is No,
Topsoil is not a good choice for starting seeds as, starting seeds require the right amount of moisture and oxygen to germinate properly.  

Topsoil does not provide this perfect balance due to its heavy, dense, packs down easily and it may also contain weed, fungi, or bacteria which can kill off your seeds. 

 If used, it will impact the growth of the seeds.  

In order to fully understand the reason for this, we need to discuss topsoil and what it really is.  

What is Topsoil?  

In the gardening community, one term that comes up frequently is “topsoil”. As a newbie or rookie gardener, you might wonder just what topsoil means.  

Topsoil is the top layer of the earth’s surface, which measures between 4 to 12 inches in depth

Due to the difference in soil composition in different areas, the texture and quality of topsoil might vary. Topsoil is known to be full of nutrients as well as rich in minerals, which is why a lot of people use it in their gardens.

Topsoil is classified into three grades, which are highlighted below:  

  • Premium Topsoil: Premium topsoil is the best grade of topsoil, also the most expensive. Premium topsoil is made up of loamy, sand and clay, as well as organic materials such as manure.

    In addition, premium grade topsoil is usually free from weed seeds. The composition of premium topsoil makes it nutrient-rich and very fertile, thereby being suitable for plant beds and other gardening purposes. 
  • General Purpose Topsoil: This grade of topsoil is not as rich in nutrients as premium topsoil. However, it is still effective enough to get the job done.

    General purpose topsoil are usually “screened”, which means that debris and stones are removed. This makes it safe for plants, thereby being suitable for plant beds and other gardening purposes.  
  • Economy Topsoil: This is the lowest grade of topsoil, also the least expensive. Economy topsoil does not undergo the screening process, so you might find stones and debris in it. It is not suitable for gardening but can be used for landscaping purposes. 

How is Topsoil Formed?  

Do you ever wonder how soil is formed?   

Topsoil is formed from decaying matter from dead plants as well as a breakdown of minerals in rocks.  

Topsoil takes a lot of years to form, as the minerals and matter break down slowly. Some reports posit that it takes up to one hundred years for an inch of topsoil to be formed. 

Why Is Topsoil Not Suitable for Starting Seeds? 

There are a few reasons why topsoil is not suitable for starting seeds. These reasons are discussed below.  

  • WeightThe weight of topsoil makes it unsuitable for starting seeds. This is because topsoil is usually too heavy and compact for seeds to germinate properly. A starting seed requires proper drainage which topsoil does not provide.

    This can therefore result in soggy soil which chokes the roots of early plans. In the same vein, the weight of topsoil also means that air circulation is restricted. 

This will prevent seeds and young plants from getting the oxygen they require to grow 

  • Diseases: Seeing that topsoil is made up of the topmost layer of the soil, it is  possible for it to carry a lot of diseases . 
    The seeds will be exposed to several pathogens, insects and disease organisms that can affect their growth. Insects in particular enjoy eating roots of plants as well as young leaves. This will give your seeds the worst start possible.  

What is Topsoil Used For ?  

Seeing that topsoil is not suitable for starting seeds, you might wonder how it is used by gardeners. There are a good number of uses for topsoil, in gardening as well as other areas. Below are some of the purposes of topsoil.  

  • Topsoil For Gardens: Topsoil has a lot of uses when it comes to gardening. It can be used to start a new plant bed and to replenish the existing garden beds in your home.

    For plant beds, a 2-inch thick layer of topsoil will do the trick. Just add this volume of topsoil to existing soil and mix them together. This can be followed by the addition of an extra layer of topsoil as topping.

    Topsoil contains nutrients, minerals and other materials that will help your plants grow.  
  • Topsoil For Lawns: A lot of people are not aware of this fact, but topsoil is a good choice for repairing damaged lawns. The areas of your lawn with bare and low spots will benefit greatly from topsoil.

    A 2-inch layer of topsoil is just about enough to get your lawn back. Simply spread the topsoil over the lacking areas of the lawn, and spread using a shovel.  
  • Topsoil For Drainage: Topsoil can also be used to fix poor soil and amend soil drainage. For areas of the soil that hold water, topsoil combined with compost will improve the quality of drainage, ensuring that water gets to the root of your plants.  

Will vegetables grow in topsoil only? 

Most will, but they won’t have a great yield.  You won’t get the best flavors from those vegetables, and the sizes are smaller as well!  

What Is The Best Soil to Start Seeds? 

The best soil to use for starting seeds indoors shouldn’t contain soil at all 

Lots of seed starting mixes on the market, but you cannot be too sure about their qualities.  

As the starting stage is the most crucial step in the gardening process. You need to use high-quality soil,  

So making your own mix is a great option for seed starting.     

Homemade seed starting mix is way better than commercial bagged because it allows you to control the quality of the soil, flexibility to be able to adjust the ingredients and also saves you money. 

DIY seed-starting mix – how to make it. 

This recipe is super easy to make and all ingredients are easy to find, whether buy from the garden center or shop online. 

And another good thing is you can make as much or as little as you need.  

Basic Recipe for Seed-Starting Mix 

You will need,  

Ingredients :

  • 4 parts compost or worm casting 
  • 1 part perlite 
  • 1 part vermiculite 
  • 2 parts (pre-moistened) Coco coir or peat moss 

Compost or worm casting:  add more beneficial microbes to your seedlings / you can buy worm casting here 

Perlite:  Provide good drainage & soil aeration 

Vermiculite:  Helps the soil retain moisture & nutrient retention 

Coco coir or peat moss: Absorbs and helps retain moisture, improves the soil structure

If you are interested in purchasing all ingredients, here are great selections on Amazon with thousands of customer reviews.

Here is how to make it

  • Mix all ingredients together in a bucket or a  bowl , until they are well blended.  
  • Add some water, make sure just have enough moist, not soaking wet. 
  • Then you can fill the mix in seedling trays and start planting seeds right away. 
DIY Seed-Starting Mix

Essential Conditions That Are Required for Efficient Seed Starting 

  • Water: Water is needed by seeds in order to germinate. This is why it is important that your starting mix has moisture retention.

    While your starting soil needs to retain moisture, it is also important that effective drainage is available.

    This will ensure that the soil is not soggy, preventing the roots from drowning after the seeds germinate. Be sure to check the mix for moisture retention before starting the seeds.
  • Air: Proper aeration is another condition that is necessary for efficient seed starting. The roots of your seeds will need oxygen once it sprouts. Oxygen is essential for plants to put their roots in the ground firmly, so you must be sure to use mix that allows for air circulation.  
  • Free From Harmful Organisms: You do not want your seed to die, before it has a chance to grow. Predators will prevent your seeds from growing into healthy plants.

    This is why you must ensure that your seeds are free from predators at the starting stage. These predators include mold and insects. Be sure to keep your starting mix free from insects, mold and other harmful plant predators.  
  • Space: Another thing that seeds require at the starting stage is space. This will ensure that their roots have enough room to grow, when the seeds finally sprout.  

Final Thoughts

If you would like to start seedling indoor, using Topsoil is not recommended, making your own starting mix is a great choice. 

It allows you to control the quality of the soil and the flexibility to adjust the ingredients as you like for the best yield.